The light green narrow leaves in this picture are the equivalent of the flowers of this tree, or more correctly they are called Bracts (similar to the red leaves of a Poinsettia) and in a week or two there should be some little pea sized seeds within these bracts.
Sycamore trees have already set their seeds and the clusters are already visible between the leaves, but they will take a while yet before they start to fall and spin like tiny helicopters to disperse themselves away from the parent tree.
I had noticed that the Swallows were late arriving this year and I believe it is down to the volcanic ash that disrupted the air space over the UK. Not that the ash stops them flying, but rather the strong Northerly winds that kept the ash cloud over the UK was stopping them from flying up North from Africa. I did find an area with a water meadow adjacent to the canal and I stood for some time watching them fly in and swoop over the water catching insects. I could hear what seemed to be their call as they flew back and forth between the meadow and canal. It is difficult to describe, but was remarkably loud and seemed to have three parts to it. I do have a sound option on my camera but it is difficult to put it onto this forum, neither could I get a decent picture, they are just too fast unless you can set up a picture using a tripod. But for anyone interested you can view the bird and listen to the song by clicking Here and then clicking the sound icon below the picture. The last bit of sound on the clip is not a Swallow but the crow of a Cockerel

I did manage to get one blurred picture while I was taking a photo of a lock gate and realised that there was actually a Swallows nest directly under the small pedestrian bridge that sits above it, they certainly build in some strange places.
The Swallow is circled near the center and the nest is under the bridge steelwork on the left hand side.
The nest (not very clear)
Lots of wild flowers are starting to bloom, the usual Buttercups can be seen along the towpath with White and Red clover among the many grasses that can be found in the adjacent fields.
Common Buttercups
Red & White Clover
The Foxgloves are just starting to appear in the more shady parts of the walk and if you are really lucky you may just spot a rare albino one. Another one to look out for is the herb Comfrey which is also known by country folk as ‘Knitbone’ due to its medical properties, in sunny weather it can be seen covered in large Bumble bees drinking the nectar. The common Foxglove (Digitalis purpurea) was the original source of herbal heart treatments and the whole plant is highly toxic.
Albino Foxglove
Comfrey (Knitbone)
And finally for this section here is ‘Donald’ and he or she is another Albino as is really a Mallard, although it looks more like an Aylesbury duck. It is not a true Albino as it has black eyes, it is more likely to just be a genetic aberration.